Papers by Author: Suchada Chantrapromma

Abstract: Drug discovery from natural products resources have been extensively studied. The most important step in the discovery process is the identification of compounds with interesting biological activity. Single crystal X-ray structure determination is a powerful technique for natural products research and drug discovery in which the detailed three-dimensional structures that emerge can be co-related to the activities of these structures. This article shall present (i) co-crystal structures, (ii) determination of absolute configuration and (iii) the ability to distinguish between whether a natural product compound is a natural product or a natural product artifact. All these three properties are unique to the technique of single crystal X-ray structure determination.

Abstract: A series of 3,5-substituted-4,5-dihydro-1H-pyrazole-1-carbothioamide derivatives were synthesized. Their structures were determined on the basis of spectroscopic data interpretation and their tyrosinase inhibitory activity was determined. The results showed that compound 2 (at 1.00 mg/mL) exhibits significant tyrosinase inhibitory activity with % inhibition of 91.866 ± 2.086 with L-tyrosine as substrate whereas compound 3 (at 1.00 mg/mL) exhibits significant tyrosinase inhibitory activity with % inhibition of 79.266 ± 0.552 and 89.593 ± 1.015 with L-tyrosine and L-DOPA as substrates. The IC₅₀ values of compounds 2 and 3 were further determined comparing with kojic acid and resveratrol. It was found that IC₅₀ values of compounds 2 and 3 were 0.391 ± 0.017 and 0.259 ± 0.005 mg/mL., with L-tyrosine as substrate, which were lower than those of the standard tyrosinase inhibitory resveratrol (0.965 ± 0.016 mg/mL).